Darwinism came at the desired time; Darwin’s theory that man is the descendant of a lower animal destroyed the entire foundation of Christian dogma. It is for this reason that as soon as Darwinism made its appearance, the bourgeoisie grasped it with great zeal. This was not the case in England. Here we again see how important the class struggle was for the spreading of Darwin’s theory. In England the bourgeoisie had already ruled a few centuries, and as a mass they had no interest to attack or destroy religion. It is for this reason that although this theory was widely read in England, it did not stir anybody; it merely remained a scientific theory without great practical importance. Darwin himself considered it as such, and for fear that his theory might shock the religious prejudices prevailing, he purposely avoided applying it immediately to men. It was only after numerous postponements and after others had done it before him, that he decided to make this step. In a letter to Haeckel he deplored the fact that his theory must hit upon so many prejudices and so much indifference that he did not expect to live long enough to see it break through these obstacles. But in Germany things were entirely different, and Haeckel correctly answered Darwin that in Germany the Darwinian theory met with an enthusiastic reception. It so happened that when Darwin’s theory made its appearance, the bourgeoisie was preparing to carry on a new attack on absolutism and junkerism. The liberal bourgeoisie was headed by the intellectuals. Ernest Haeckel, a great scientist, and of still greater daring, immediately drew in his book, “Natural Creation,” most daring conclusions against religion. So, while Darwinism met with the most enthusiastic reception by the progressive bourgeoisie, it was also bitterly opposed by the reactionists. The same struggle also took place in other European countries. Everywhere the progressive liberal bourgeoisie had to struggle against reactionary powers. These reactionists possessed, or were trying to obtain through religious followers, the power coveted. Under these circumstances, even the scientific discussions were carried on with the zeal and passion of a class struggle. The writings that appeared pro and con on Darwin have therefore the character of social polemics, despite the fact that they bear the names of scientific authors. Many of Haeckel’s popular writings, when looked at from a scientific standpoint, are very superficial, while the arguments and remonstrances of his opponents show unbelievable foolishness that can only be met in the arguments used against Marx.